1、 Access to Additional Content for ECA TEP105-11-B, Dated: June 2000 (Click here to view the publication) This Page is not part of the original publication This page has been added by IHS as a convenience to the user in order to provide access to additional content as authorized by the Copyright hold
2、er of this document Click the link(s) below to access the content and use normal procedures for downloading or opening the files. Excel file 99-10-5 TEP LOCIE Information contained in the above is the property of the Copyright holder and all Notice of Disclaimer m 11-1 the visible shui;lri be n grea
3、ter thcrt: 8 (-WW?J: si74 prefer;ib!y $30 greatur :bm 4 -P 4.4 A measuring shutter that closes to determine the dark level and the true zero of signal. TEP-105-11-6 Color measurement and white Set-up procedure for CRT screens Page 3 I. I d i t 1.2 400450500550600650700 5 Tubesetup Nominal settings a
4、re: full raster scanning with blanking, beam at normal focus, approximately one milliampere average beam current in each primary field per square meter of screen area. View the primary fields individually and measure the x and y chromaticity coordinates and luminance of each primary field with a spe
5、ctroradiometer. Determine the writing speed and raster excitation density by recording the horizontal and vertical line separations in a standard crosshatch pattern (see figure 3). Enter the crosshatch line spacing into the data sheet labeled annex A.1. Also record in annex A.1 a measured or estimat
6、ed value of the panel glass transmittance, anode voltage, matrix openings of the red, green, and blue phosphor elements, horizontal screen period, and screen area. STDOEIA TEPLOS-LI-B-ENGL 2000 3239b00 Ob57707 T2T TEP-105-11-B Color measurement and white Set-up procedure for CRT screens Page 4 n The
7、 area of measurement of x. y, and luminance on the CRT screen is represented by the circle. The nearest pairs of horizontal and vertical crosshatch lines are also shown. “h” is the horizontal crosshatch period, typically several microseconds, and ”n” is the number of blanked horizontal lines per ver
8、tical crosshatch period, typically 18. Figure Ctandard crosshatch pattern 6 Enter into annex A.l of the data sheet the spectroradiometer x, y, and luminance data from the blanked rasters of each primary field. Record the average beam current used during the blanked raster measurement of x, y, and lu
9、minance of each primary field The relative RGB primary luminances for setting up the white are shown in the worksheet annex A.3 report form. The x and y white point chromaticities must be entered on that sheet in the fourth and fifth data rows as indicated. In the present example, the results for th
10、e primary luminance mixtures are 22.6% red, 67.7% green, and 9.8% blue, based on the spectroradiometer x and y readings recorded in annex A.1. The following L=AQ equation shows the algebra of matrix multiplication which produces the above result from the spectroradiometer x and y data. Here L, the r
11、elative luminances, appears as expressions on the right hand side of equation 3. Matrix A is the inverse of the normalized chromaticity matrix of the three primary fields, and Q is the normalized chromaticity vector of the white point: Chromaticity matrix and white point setup The relative RGB lumin
12、ance mixture for white point setup is given in equation 3: STD-EIA TEPLOS-11-B-ENGL 2000 323qb00 Ob577LO ?i1 W TEP-IOB-11-B Color measurement and white Set-up procedure for CRT saeens Page 5 Referring again to annex A.3, the report forms, and an example for the A and Q matrices is spelled out in the
13、 first three rows of data. Thus xr/y = 1.714, etc. Also shown in worksheet annex A.3 are the primary beam currents for producing a luminance of 500 Cdh2 at the white color. This information, along with the frontal luminance efficiencies and the luminous efficacies, comes from the luminance and beam
14、current data in annex A.1. 7 Luminance normalization, frontal luminance efficiency, and luminous efficacy The important test parameters: anode voltage, anode current, and raster scan size are set to typical values a tube would see when in use. We suggest one milliampere average beam current per squa
15、re meter of screen area using full raster scanning. These parameters affect the excitation density, which must be accurately and precisely known at the region viewed by the spectroradiometer. For a blanked raster, the beam is turned off during the horizontal and vertical retrace periods, so that the
16、 average anode current will be up to 30% less than the instantaneous current. Also unique to CRT displays is the issue of raster scanning linearity, where the beam writing speed is not necessarily uniform from tube to tube or even at all screen points in a given tube. We show how to normalize the lu
17、minance readings to standard conditions of writing speed in order to obtain accurate data in every measurement. The ratio of peak current to average current that is affected by the timing of the blanking signals is also taken into account. Luminance reading normalization is most important when one w
18、ishes to determine efficiencies. Frontal luminance efficiency, for example, is the ratio of the luminance to the driving power of the CRT. Luminous efficacy is the ratio of the luminous flux to the power into the phosphor screen. In order to accurately obtain the luminous flux one must start with th
19、e normalized luminance and multiply it by the screen area. The luminance-normalizing factor C defined in equation 6 comprises all the necessary factors to adjust the luminance readings and get accurate efficiency data. The luminance normalization factor is equal to the ratio of the ideal to the actu
20、al average power density. The ideal power density is equal to the current-voltage product divided by the screen area. If the total picture area of the screen is taken to be A, then the ideal average power density is given by equation 4 IV Ideal power density = - A (4) where I is the average anode cu
21、rrent. The true power density is calculated from the writing speed and raster line density at the measured region of the screen. These parameters are determined by use of a video crosshatch pattern. Equation 5 also includes the effects of the horizontal and vertical retrace periods on the peak to av
22、erage beam current ratio: STD-EIA TEPLO5-11-B-ENGL 2000 m 3234b00 Ob57733 b88 m TEP-105-1 1-6 Color measurement and white Set-up procedure for CRT screens Page 6 where IVfphnN rs True power density= (5) is the horizontal distance between consecutive vertical crosshatch lines in the measuring field a
23、rea; is the vertical distance between consecutive horizontal crosshatch lines in the measuring field area; is the average anode current; is the anode potential; is the frame rate is the ratio of peak current to average current, determined by the retrace blanking periods; is the horizontal cross hatc
24、h period, or the time between consecutive vertical cross hatch lines; is the number of blanked horizontal lines per field between consecutive horizontal crosshatch lines; is the number of fields per frame. The luminance normalization factor is given in equation 6: rs AfphnN C= C, the luminance norma
25、lization factor, will multiply the luminance readings obtained in annex A.1. This allows for accurate efficiency data to be obtained in every measurement even when the scanning linearity is not perfectly uniform across the entire raster. One need only remember to enter into annex A.l the crosshatch
26、distances appropriate to the measured areas of the screen. Scanning, blanking, and crosshatch timing parameters also need to be entered into the worksheet. A special data , annex A.2, is reserved for recording these parameters. The worksheet will automatically produce C using equation 6 and apply it
27、 as the luminance normalization factor, provided that the crosshatch signal parameters h and n, the scanning parameters fand N, and the horizontal and vertical blanking parameters that determine p, are properly entered into annex A.2 of the worksheet. The efficiencies and the beam currents, reported
28、 in annex A.3, are corrected by the C factor. Area and transmission factors are also listed in annex A.3, the report of the worksheet. These factors are the assumed or measured glass transmittance, the matrix transmission, and the screen area. They determine the factor by which the frontal luminance
29、 efficiencies are multiplied to produce the luminous efficacies. 8 Twotomponent mixtures The procedure for calculating mixtures of two primaries is similar to the tricolor case in 6 above, except that instead of a 3 X 3 matrix one now uses a 2 X 2. Each column consists of X and (X+Y+Z) instead of X,
30、Y, and Z. 9 Luminance colorimeters If carefully tailored filterlphotodetector spectral responses of a colorimeter can be matched exactly to the distribution coefficients for equal energy (x-bar, y-bar, and z-bar curves shown in figure 2), then the readings from that colorimeter will accurately give
31、the X,Y, and Z color component information. Colorimeters do not have diffraction gratings and multielement 200 detector arrays. But it is difficult to achieve accuracy in fitting the distribution curves of the Standard Observer with optical filters. Errors in chromaticity may be as high as t 0.03. T
32、his is three times the range of error expected in chromaticity values from a spectroradiometer. TEP-105-1 1-B Color measurement and white set-up procedure for CRT screens Page 7 Annex A Data sheet and spreadsheet calculations A.l CRT color measurement data sheet for white point setup and frontal lum
33、inance efficiency See accompanying ExcelTM file, 99-1 0-5 TEP LOCIE.xls. A.2 CRT scan parameters in the luminance normalization factor See accompanying ExcelTM file, 99-10-5 TEP LOCIE.xls. A.3 Report sheet for white calculations and efficiencies setup See accompanying ExcelTM file, 99-10-5 TEP LOCIE
34、.xls. 118 3234bUU Ilb3D257 394 a TE P-105-11 -B Color measurement and white Set-up procedure for CRT screens Page A.l Part 1 - CRT Color Measurement Data Sheet for White Point Set-up and Frontal Luminance Efficiency Date Tube ID Test Sample Glass Transmittance 0.36 Anode Voltage - kV 30 Matrix Openi
35、ngs Red - mils 7 Green - mils 7 Blue - mils 7 Screen Period - mils 28 Primary Average Horizontal Vertical Field current cross-hatch cross-hatch mic.Amps cm cm R 200 3.6 3.3 G 200 B 200 Previous page is blank TEP-105-11-B Color measurement and white Set-up procedure for CRT screens Page A.2 Part 2 -
36、CRT Scan Parameters in the Luminance Normalization Factor Percent of horizontal scan period in blanking Percent of vertical scan period in blanking Ratio of instantaneous peak to time-average current Bh 18 Bv 10 P 1.36 Frame Frequency - Hz f 30 Horizontal Cross-hatch Time Interval - microseconds h 3
37、.2 Number of horizontal lines in one vertical cross-hatch interval 18 Number of Fields per Frame Nf 2 n 1 Lu mina nce Norma I iza tion Factor C 1.161 TEP-105-11 -B Color measurement and white Set-up procedure for CRT screens Page A.3 Part 3 - Report Sheet for Set-up White Calculations and Efficienci
38、es Tube ID Test Sample Normalized Chromaticity Matrix (A inverse) followed by norm. white vector CIE x coordinate of Set-up White CIE y coordinate of Set-up White Relative Luminances for Set-up White R G B Frontal Luminance Efficiencies - Cd/mA2/W R G B W Area and Transmission Factors Luminous Effic
39、acies - LIW K G B R G B W Beam Currents for 500Cd/mA2 Luminance R G B W at Set-up White - mA 1.714 0.500 2.500 1 1 1 0.1 43 0.167 13.167 0.285 0.294 22.6% 67.7% 9.8% 2.3 8.7 1.2 3.8 2.438 2.438 2.438 17.7 66.4 8.9 29.5 1.63 1.30 1.41 4.33 0.969388 1 1.431 973 - - STD.EIA TEPLOS-IL-B-ENGL 2000 3234b0
40、0 Ob599L5 223 8 Signature: EU Document Improvement Proposal Date: If in the review or use of this document, a potential change is made evident for safety, health or technical reasons, please fill in the appropriate information below and mail or FAX to: Electronic Industries Alliance Engineering Depa
41、rtment - Publications Office 2500 Wilson Blvd. Arlington, VA 2220 1 FAX: (703) 907-7501 Document No. Document Title: Submitters Name: Telephone No.: FAX No.: e-mail: Address: I Urgency of Change: bediate: 0 At next revision: Problem Area: a. Clause Number andor Drawing: c. ReasonRationale for Recommendation: Additional Remarks: FOR EIA USE ONLY Responsible Committee: Chairman: Date comments forwarded to Committee Chairman:
